%0 Journal Article %1 Maji.2007 %A Maji, Somnath %A Sarkar, Biprajit %A Mobin, Shaikh M. %A Fiedler, Jan %A Kaim, Wolfgang %A Lahiri, Goutam Kumar. %D 2007 %J Dalton Transactions %K acetylacetonate complex crystal dinuclear electrochem hydroxyphenyl mononuclear pentanedionate phenylazopyridine prepn pyrazine pyrazine;ruthenium redox;spectroelectrochem ruthenium structure %N 23 %P 2411--2418 %R 10.1039/B701511A %T Non-innocent behaviour of ancillary and bridging ligands in homovalent and mixed-valent ruthenium complexes [A2Ru(m-L)RuA2]n, A = 2,4-pentanedionato or 2-phenylazopyridine, L2- = 2,5-bis(2-oxidophenyl)pyrazine %X Structurally characterized 2,5-bis(2-hydroxyphenyl)pyrazine (H2L) can be partially or fully deprotonated to form [(acac)2Ru(m-L)Ru(acac)2], [1], acac- = acetylacetonato = 2,4-pentanedionato, [(pap)2Ru(m-L)Ru(pap)2](ClO4)2, [2](ClO4)2, pap = 2-phenylazopyridine, or [(pap)2Ru(HL)](ClO4), [3](ClO4). Several reversible oxidn. and redn. processes were obsd. in each case and were analyzed with respect to oxidn. state alternatives through EPR and UV-visible-NIR spectroelectrochem. In relation to previously reported compds. with 2,2'-bipyridine as ancillary ligands the complex redox system [1]n is distinguished by a preference for metal-based electron transfer whereas the systems [2]n and [3]n favor an invariant RuII state. Accordingly, the paramagnetic forms of [1]n, n = -, 0, +, exhibit metal-centered spin whereas the odd-electron intermediates [2]+, [2]3+ and [3] show radical-type EPR spectra. A comparison with analogous complexes involving the 3,6-bis(2-oxidophenyl)-1,2,4,5-tetrazine reveals the diminished p acceptor capability of the pyrazine-contg. bridge. [on SciFinder(R)]

@article{Maji.2007, abstract = {Structurally characterized 2,5-bis(2-hydroxyphenyl)pyrazine (H2L) can be partially or fully deprotonated to form [(acac)2Ru(\textgreek{m}-L)Ru(acac)2], [1], acac- = acetylacetonato = 2,4-pentanedionato, [(pap)2Ru(\textgreek{m}-L)Ru(pap)2](ClO4)2, [2](ClO4)2, pap = 2-phenylazopyridine, or [(pap)2Ru(HL)](ClO4), [3](ClO4). Several reversible oxidn. and redn. processes were obsd. in each case and were analyzed with respect to oxidn. state alternatives through EPR and UV-visible-NIR spectroelectrochem. In relation to previously reported compds. with 2,2'-bipyridine as ancillary ligands the complex redox system [1]n is distinguished by a preference for metal-based electron transfer whereas the systems [2]n and [3]n favor an invariant RuII state. Accordingly, the paramagnetic forms of [1]n, n = -, 0, +, exhibit metal-centered spin whereas the odd-electron intermediates [2]+, [2]3+ and [3] show radical-type EPR spectra. A comparison with analogous complexes involving the 3,6-bis(2-oxidophenyl)-1,2,4,5-tetrazine reveals the diminished \textgreek{p} acceptor capability of the pyrazine-contg. bridge. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Maji, Somnath and Sarkar, Biprajit and Mobin, Shaikh M. and Fiedler, Jan and Kaim, Wolfgang and Lahiri, Goutam Kumar.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2c3cc53f178b76e7a89ea71bf254bdc39/huebleriac}, doi = {10.1039/B701511A}, interhash = {e31c745f5cda892a66945c40f4e084e8}, intrahash = {c3cc53f178b76e7a89ea71bf254bdc39}, issn = {1477-9226}, journal = {Dalton Transactions}, keywords = {acetylacetonate complex crystal dinuclear electrochem hydroxyphenyl mononuclear pentanedionate phenylazopyridine prepn pyrazine pyrazine;ruthenium redox;spectroelectrochem ruthenium structure}, number = 23, pages = {2411--2418}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Non-innocent behaviour of ancillary and bridging ligands in homovalent and mixed-valent ruthenium complexes [A2Ru(\textgreek{m}-L)RuA2]n, A = 2,4-pentanedionato or 2-phenylazopyridine, L2- = 2,5-bis(2-oxidophenyl)pyrazine}, year = 2007 }